<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="/js/vue.js"></script>
</head>
<body>
  <div id="app">
      <p>{{msg}}</p>
  </div>
<br>
  <script>
   let app = new Vue({
   el:"#app",
   data:{ 
    val:"简单对象初始值",
    obj:{
        name:"复杂对象name",
        value:"复杂对象value"
    },
    watch:{
        val:function(newval,oldval){
            console.log(this.val);
        }
    },
    obj:{
        deep:true,
        handler:function(new_val,old_val){
            console.log(new_val,old_val);

        }
    }
      }
    })
  </script>
</body>
</html>